改性膨润土吸附废水溶液中甲醛的性能研究

Study on the performance of adsorbing formaldehyde from wastewater solution with modified bentonite

以十二烷基二甲基苄基氯化铵作阳离子表面活性剂,十二烷基苯磺酸钠作阴离子表面活性剂,按一定配比混合对膨润土进行改性,探究其对废水溶液中甲醛的吸附条件,并考察了阳、阴离子表面活性剂用量、改性膨润土投加量、pH和吸附平衡时间等对吸附效果的影响。结果表明,向25 mL pH=5.0的甲醛废水中投加1.5 g改性制得的阴阳离子膨润土,在(25±1)℃下恒温搅拌吸附150 min后,改性膨润土对甲醛的吸附率达28.9%。其吸附热力学模型为ln K=899.6/T-1.786 1,该吸附反应能在常温下自发进行,且温度升高对吸附不利。

The bentonite has been modified by dodecyldimethylbenzylammonium chloride as cationic surfactant and sodium dodecyl benzene sodium sulfonate as anionic surfactant, according to a certain proportion. The adsorption conditions of formaldehyde from wastewater are explored. The effects of the dosage of anionic and cationic surfactants,dosage of modified bentonite,pH and adsorption balance time on the adsorption efficiency are investigated. The results indicate that 1.5 g of modified bentonite is added to 25 mL of formaldehyde wastewater which pH is 5,0. After being stirred for 150 min,at（25＋1 ） ℃ ,the adsorption rate of formaldehyde by modified bentonite can reach 28.9%. Its adsorptive thermodynamics model is In K=899.6/T-1.786 1. The adsorption reaction can be carried out spontaneously at normal temperature. And, temperature rise is not good for adsorption.